Stopcock



FIG. 1 is a front view of a stopcock showing my new design in accordance with an embodiment;

FIG. 2 is a back view of the stopcock of FIG. 1;

FIG. 3 is a left side view of the stopcock;

FIG. 4 is a right side view of the stopcock;

FIG. 5 is a top view of the stopcock;

FIG. 6 is a bottom view of the stopcock; and,

FIG. 7 is a front perspective view of the stopcock. 

CLAIM The ornamental design for a stopcock, as shown and described. 